Low profile rolling support assembly

ABSTRACT

Disclosed is a low profile rolling support assembly useful for supporting loads above a supporting surface where at least one end of the rolling support assembly is positionable beneath a structure having minimal clearance above the supporting surface. The rolling support assembly includes a load bearing member and a caster assembly containing a wheel where the load bearing member extends laterally away from the caster assembly at substantially the same height or less as the caster assembly.

BACKGROUND

In various situations it is sometimes desirable to lift or support aload above a surface where using a free-standing support structurehaving lower lateral support members that can be positioned underneathlow lying obstacles. For example, in a manufacturing setting, it mightbe desirable to use a lift to assist in maneuvering the component partsof a machine into position where the clearance under the machine isminimal. Likewise, medical imaging devices are often rolled intopositioned suspend over a patient lying in a bed or on a table that mayextend close to floor. Considering still other examples, it might beadvantageous for certain drill presses, milling machines, radiant heatdryers for curing inks or dyes, large magnifying glasses, and some typesof tables to be suspended above a structure with a very low clearanceabove the floor without interfering with it. In these situations, itmight be preferable for the laterally extending support members tomaintain a low profile to allow them to be positioned beneath otherstructures thereby allowing for better positioning of the load beingsupported above.

One example of where such a structure might be used in the healthcarefield concerns patient lifts. It is often desirable to assist a patientto a standing or suspended position in cases where, for example, thepatient is infirm or disabled and lacks the strength or coordination tostand without aid. It is common in such situations for a caregiver toassist a patient using a patient lift.

Two types of patient lifts are commonly used and examples of each aredisclosed below. One type helps raise the patient from a sittingposition to a generally standing position. The patient is supported byeither holding onto support bars, or by wrapping a strap-type slingbehind the patient's back and under the patient's arms. The sling orsupport bars are attached to a support arm which is raised and loweredby a lifting mechanism. In this way, a caregiver can assist insupporting the patient as the patient moves from a seated position to agenerally erect position.

The second type of patient lift requires the patient to be placed in asling or stretcher on a bed or chair. The sling or stretcher is thenconnected to a support arm which is raised and lowered by a liftingmechanism actuated by the caregiver. With this type of lift, the patientis completely supported from an overhead position, and has no activerole in supporting themselves or assisting in being raised. Such a liftcan temporarily raise a patient or transport them with minimaldiscomfort.

With both types of patient lifts, as with other examples cited above, itis often the case that the lift or stand has corresponding laterallyextending support members at the lower extremity of the lift whichsupport the lift structure and the load. It is often preferable thatduring use of a patient lift or similarly supported device that thelower supporting members extend laterally beneath whatever structure theload (in this case a patient) is resting on (like a hospital bed orchair). Because some of the structures the load is resting on extendclose to the floor, it is often the case that those structures interferewith the positioning of the laterally extending support members on thelift or stand.

SUMMARY

A low profile rolling support assembly is disclosed. The rolling supportassembly includes a low profile caster assembly configured to support aload bearing member extending laterally away from the side of the casterassembly. One embodiment of the caster assembly includes a rotatingwheel that is pivotally mounted to a hub configured to transfer weightresting on the load bearing member to the floor through the wheel. Boththe caster assembly and the load bearing member extend above the floorabout the same height as the wheel thus reducing the chance ofinterference between the rolling support assembly and lower members of astructure with a low clearance height underneath, for example a hospitalbed, table, or chair the patient may be resting on.

Further, additional embodiments will be apparent to those skilled in theart from the Detailed Description herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an exploded view of a preferred embodiment of a low profilerolling support assembly.

FIG. 2 is a cross-sectional side view of the rolling support assembly ofFIG. 1.

FIG. 3 is a magnified view of one end of the rolling support assembly ofFIG. 2.

FIG. 4 is one embodiment of a prior art patient lift modified to includethe low profile rolling support assembly of FIGS. 1-3.

FIG. 5 is another embodiment of a prior art patient lift modified toinclude the low profile rolling support assembly of FIGS. 1-3.

DETAILED DESCRIPTION

For the purpose of promoting an understanding of the principles of theinvention, reference will now be made to certain embodiments, some ofwhich are illustrated in the drawings, and specific language will beused to describe the same. It will nevertheless be understood that nolimitation of the scope of the invention is thereby intended. Anyalterations and further modifications in the described embodiments, andany further applications of the principles of the invention as describedherein are contemplated as would normally occur to one skilled in theart to which the invention relates.

The uses of the terms “a” and “an” and “the” and similar references inthe context of describing the invention (especially in the context ofthe following claims) are to be construed to cover both the singular andthe plural, unless otherwise indicated herein or clearly contradicted bycontext. Recitation of ranges of values herein are merely intended toserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the invention.

Illustrated in FIG. 1 is a rolling support assembly 10 useful forsupporting an article such as a patient lift or other load above asupporting surface in situations where clearance under a potentialinterfering structure may be minimal. A longitudinal load bearing member20 is shown having a first end 21, a second end 26, a mount 24 and anattachment region 22. A caster assembly 30 is positioned at second end26 such that load bearing member 20 approaches caster assembly 30laterally from a side, and extends laterally away from the correspondingside. As will be described in greater detail below, forces appliedvertically to load bearing member 20 are therefore transmittedsubstantially horizontally through load bearing member 20 to casterassembly 30 and attachment region 22.

As shown in FIGS. 1 and 2, caster assembly 30 includes a frame 31, hub46, and wheel 39. Frame 31 has a side wall 33 that provides structureand rigidity to caster assembly 30 and operates to transfer forcestransmitted through load bearing member 20 to hub 46. Hub 46 ispivotally mounted or rotatably coupled within a central opening 37defined by frame 31, shown in FIGS. 1 and 2 as a substantially circularopening. The mounting or coupling of hub 46 to frame 31 is achieved by aretaining member 52 and a bearing assembly 51 which together have asmaller inner diameter than the outer diameter of hub 46. Retainingmember 52 is preferably a flange, ring, series of studs, pins, screws,or other projecting members as shown in FIG. 1-3. However, retainingmember 52 can also be an inset, groove, or other similar structurewherein bearing assembly 51 is lodged or otherwise fixed to frame 31.Regardless of the embodiment used, this arrangement causes retainingmember 52 to maintain hub 46 in place together with frame 31 inoperation when both structures receive vertical pressure under the forceof a load applied to load bearing member 20. Hub 46 also has a wheelmount 44 to which wheel 39 is pivotally mounted to rotate around an axle41 coupled to wheel mount 44. As force is transmitted to hub 46 fromframe 31, these forces are in turn transferred to axle 41 and to wheel39.

Also shown in FIG. 1 are specific details indicating how wheel 39 ispivotally mounted to axle 41. Wheel 39 has a width 40 and rotates aroundan axis of rotation defined by axle 41 which is supported by wheel mount44. In the embodiment of hub 46 shown in FIGS. 1-5, hub 46 has a wheelopening 47 into which wheel 39 is inserted. Wheel mount 44 coincideswith wheel opening 47 such that wheel 39 freely rotates within wheelopening 47. As shown in FIG. 1, wheel 39 is supported on axle 41 bywheel bearing assemblies 37 which are arranged along axle 41 withwashers 36 between them. Therefore when wheel 39 and axle 41 are finallypositioned in hub 46, axle 41 passes through wheel mount 44, wheelbearing assemblies 34, and washers 36. Wheel 39 is positioned on theoutside of wheel bearing assemblies 34 so that wheel bearing assemblies34 are between wheel 39 and axle 41 thus providing rotatable supportbetween axle 41 and wheel 39. With this arrangement, wheel 39 rotatesaround axle 41 while axle 41 is stationary within mount 44. Axle 41 ismaintained in wheel mount 44 by axle retaining rings 32 which arepositioned on opposing ends of axle 41, preferably in grooves, ornotches, against positioning flanges, or by other similar retainingstructures. In this manner axle 41 remains fixed in position withrespect to hub 46.

Hub 46 optionally includes a cover 56 having an opening 53 and coverscrew holes 58. Cover 56 is mounted to the top surface of hub 46 andfixed in place using screws 59 which are positioned through cover screwholes 58 into hub screw holes 48. In the embodiments shown, cover 56 ispositioned so as not to interfere with the rotational movements of hub46. Opening 53 allows the upper extent of wheel 39 to be positionedclose to the top of caster assembly 30 without projecting beyond the topof caster assembly 30. Therefore, caster assembly 30 can be said tocontain wheel 39 in that wheel 39 projects from the bottom of casterassembly 30 to contact a supporting surface, but does not project fromthe top so as to avoid interfering with an article, or object thatrolling support assembly 10 may need to fit below. Other embodiments ofcover 56 are envisioned, such as a cover positioned over frame 31 thusavoiding the need for an opening 53. However this is less advantageousbecause it adds height to caster assembly 30 beyond the height of frame31 whereas the embodiment shown in FIG. 1 does not. Various otherpurposes for cover 56 are also envisioned which include, withoutlimitation, reducing the risk of injuries caused by users whoaccidentally interfere with the moving parts within caster assembly 30,and/or reducing the size and quantity of foreign object debris enteringcaster assembly 30 from above.

Caster assembly 30 further includes a bearing assembly 51 for reducingthe friction caused by the rotation of hub 46 relative to frame 31.Bearing assembly 51 is held in place between retaining member 52 andbearing retaining ring 49. Bearing retaining ring 49 is positioned onthe opposite side of bearing assembly 51 from retaining member 52 tomaintain bearing assembly 51 within central opening 37 when casterassembly 30 is disengaged from a supporting surface. When rollingsupport assembly 10 is in operation, retaining member 52 transfersvertical and horizontal forces applied to frame 31 to bearing assembly51 so that force applied vertically to caster assembly 30 is transferredto hub 46. Bearing assembly 51 thus allows hub 46 to rotate withincentral opening 37 without generating excessive friction between hub 46and frame 31. Bearing assembly 51 is preferably a ball bearing assemblyand most preferably a four-point angular contact ball bearing assembly.A four-point angular contact ball bearing assembly is preferred because,as one of ordinary skill in the art will recognize, this type of bearingassembly maintains structural and operational integrity regardless ofwhether bearing assembly 51 is repeatedly subjected to forces applied inmultiple dimensions simultaneously under load. For example, when casterassembly 30 is under load, bearing assembly 51 is subjected to bothdownward vertical forces and lateral horizontal forces such as whenrolling support assembly 10 is moved.

FIG. 2 shows a cross-sectional view of rolling support assembly 10 shownin FIG. 1 with additional detail indicating some of the geometry of theforces acting on it. Load bearing member 20 is shown supported above asupporting surface 60 by caster assembly 30 at second end 26 and rearsupport assembly 500 mounted at attachment region 22 at first end 21.Load bearing member 20 defines a load bearing axis LB that in theembodiment shown in FIG. 2 is horizontal and substantially parallel tosupporting surface 60. As shown in FIG. 2, and with reference to FIG. 1as well, load bearing member 20 abuts side wall 33 (which is the sidewall of caster assembly 30) and extends laterally away from the outersurface of side wall caster assembly 30.

With respect to FIGS. 1-5, “horizontal” and “vertical” are definedrelative to supporting surface 60, where any angle with respect tosupporting surface 60 that is less than 45 degrees can be consideredsubstantially horizontal, and an angle with respect to supportingsurface 60 that is greater than 45 degrees can be consideredsubstantially vertical. Lower angles are preferred to minimize the riseof load bearing member 20 over its run, with an angle of zero orapproaching zero for a substantial length of load bearing member 20being most preferred.

Load bearing axis LB is a reference line along which the verticalcomponents of forces acting on load bearing member 20 are transmittedthrough and along load bearing member 20 to caster assembly 30. Inanother aspect, load bearing axis LB indicates the horizontal offset ofthe vertical components of forces acting on load bearing member 20relative to the point at which load bearing member 20 extends away fromcaster assembly 30. Load bearing axis LB is therefore positioned asshown above supporting surface 60 as a central axis centered between thetop 86, or upper extent of, and the bottom 88, or lower extent of loadbearing member 20. The top 86 and bottom 88 of load bearing member 20are determined where load bearing member 20 extends away from lateralouter surface of side wall 33, which in the embodiments shown in FIG.1-5, is the lateral outer surface of caster assembly 30 as well. Statedanother way, the top 86 and bottom 88 of load bearing member 20 aredetermined where load bearing member 20 approaches the lateral outersurface of caster assembly 30. As shown in FIG. 2, load bearing axis LBis a reference line defined by load bearing member 20 but is notentirely contained by it, rather load bearing axis LB extends throughsome or all of load bearing member 20 and then extends beyond it ineither direction as well.

Hub 46 positioned within central opening 37 as described above isrotatable around a vertical support axis SA shown in FIGS. 2 and 3.Support axis SA and rear supporting axis RSA are both laterally offsetfrom a load axis LA by a portion of the horizontal span of load bearingmember 20. Among other things, load axis LA intersects and isperpendicular to the load bearing axis LB and indicates the horizontaloffset along load bearing axis LB of the force perpendicular tosupporting surface 60 exerted by a load 100 on load bearing member 20.Considering the geometry, force exerted along load axis LA istransmitted along load bearing axis LB by load bearing member 20 whereit is then transferred to supporting surface 60 along support axis SAand rear supporting axis RSA. Force transfer occurs when load axis LA,load bearing axis LB, rear supporting axis RSA, and support axis SAintersect, cross, or coincide in a manner similar to that shown in FIG.2. Therefore, the axes shown in FIG. 2 are said to be “intersecting” or“crossing” if they intersect or cross over one another with reference totheir vertical displacements relative to supporting surface 60, andtheir horizontal displacements relative to load bearing axis LB. It istherefore not necessary for axes LA, LB, RSA, or SA to actuallyintersect in three dimensional space although this interrelationship maybe indicated, suggested, or implied in the figures shown.

It is also evident in FIG. 2 that axes RSA and SA do not necessarilyindicate the horizontal displacement along load bearing axis LB of thephysical points of contact between wheel 39, rear support assembly 500and supporting surface 60. As discussed to some extent above, and as canbe seen to a greater degree in FIG. 3, forces transferred along loadbearing member 20 to caster assembly 30 are transferred first to frame31, through retaining member 52 into bearing assembly 51, then throughhub 46 to axle 41, through bearing assembly 34 into wheel 39, andfinally through wheel 39 to supporting surface 60. Stated in reverse,wheel 39 is supported by supporting surface 60 and supports bearingassemblies 34 which support axle 41. Axle 41 supports hub 46 which iscoupled to and supports bearing assembly 51. Bearing assembly 51 issupported by retaining member 52 of frame 31.

Support axis SA thus indicates the horizontal displacement along loadbearing axis LB of the vertical force on caster assembly 30 caused byload 100, not the precise horizontal offset of the contact point betweenwheel 39 and support surface 60. The remainder of the forces directedagainst load bearing member 20 not supported by caster assembly 30 aretransferred through load bearing member 20 to rear support assembly 500.As with support axis SA, rear supporting axis RSA indicates thehorizontal displacement of the vertical force on rear support assembly500, not the precise position of where rear support assembly 500contacts supporting surface 60. Rear support assembly 500 is shown inFIG. 2 as a prior art wheel assembly but may be embodied in various waysincluding various types of rolling support structures, motorized units,mobile platforms and the like.

The position of mount 24 along load bearing member 20 determines thehorizontal offset of load axis LA and the extent to which casterassembly 30 is able to support a load positioned above a low clearancestructure. For example, in the embodiments shown in FIGS. 1-3, load axisLA is offset from support axis SA by a distance greater than half thelength of load bearing member 20 because mount 24 is greater than halfthe length of load bearing member 20 away from second end 26. Thisarrangement is preferable in many instances because it allows most ofload bearing member 20 to extend beneath a structure. Therefore, when aload is applied along load axis LA, such as during a lifting operationfrom a low clearance hospital table or bed, the load is supported bycaster assembly 30 positioned approximately beneath the load under thebed or table. However, it may be preferable in some instances to movemount 24 further toward second end 26 where load axis LA is offset fromsupport axis SA along load bearing member 20 by a lesser distance suchas one third or one fourth the length of load bearing member 20. Toachieve additional reach beneath a low clearance structure, or possiblyfor other reasons, it may be advantageous to align load axis LA alongrear support axis RSA. On the other hand, it may be more preferable toalign load axis LA in the center of load bearing member 20 depending onthe circumstances. Mount 24 may be positioned almost anywhere along loadbearing member 24 depending on the desired reach of load bearing member20 and the desired offset of load axis LA relative to support axis SA.

Further detail of caster assembly 30 is indicated in FIG. 3 where anenlarged cutaway view of second end 26 of rolling support assembly 10 isshown. The top 86 and bottom 88 of load bearing member 20 are shownwhere the top 86 defines a height 85 above supporting surface 60 in thearea where load bearing member 20 extends away from caster assembly 30.Height 85 can also be thought of as a general reference point indicatinga relative height above supporting surface 60 against which otherrelative heights above supporting surface 60 can be compared. Likewise,references to the “top” 86 of load bearing member 20 can also be thoughtof as a reference point indicating a relative height above supportingsurface 60.

Likewise, caster assembly 30 has a bottom 83 and a top 78, the top 78 ofcaster assembly 30 defines height 80. These dimensions are specificheights at a given location as well as reference points relative tosupporting surface 60 as well. Heights 85 and 80 can be compared bycomparing their relative displacements above supporting surface 60. Forexample in the embodiment shown in FIGS. 1-3, the top 78 of casterassembly 30 is at the same height 80 as the top 86 of load bearingmember 20. In measuring height 80, the highest extent of caster assembly30 is considered.

Wheel 39 is similarly shown in FIG. 3 having an upper extent 70 and alower extent 75, with the distance between them being the height 72 ofwheel 39. Because wheel 39 is an example of a rolling member or rollingsupport device configured to rotate around an axis, here defined by axle41, wheel 39 does not have fixed locations serving as a “top” or“bottom.” Height 72, upper extent 70 and lower extent 75 are also to betreated both as specific dimensions at a given location as well asreference points relative to supporting surface 60. These dimensions canthen also be compared to other similar dimensions, such as the top 86 ofload bearing member 20 and the top 78 of caster assembly 30. Bycomparing their relative displacements above supporting surface 60without respect to the precise three-dimensional positioning of wheel39, the profile of caster assembly 30, load bearing member 20, and wheel39 can be measured independently or relative to one another. This isuseful because in the embodiment shown in FIG. 3, and in variousembodiments of caster assembly 30, wheel 39 is not centered withincentral opening 37 causing the physical highest point on wheel 39 tochange position in three dimensions relative to load bearing member 20and caster assembly 30 as hub 46 rotates inside frame 31. Height 72 canalso be viewed as the approximate diameter of wheel 39.

As discussed above with respect to cover 56, and opening 53, wheel 39 iscontained within caster assembly 30 with upper extent 70 of wheel 39preferably at or below the top 78 of caster assembly 30 while lowerextent 75 of wheel 39 projects below bottom 83 of caster assembly 30 tocontact supporting surface 60. In the embodiment shown in FIG. 3, top 86of load bearing member 20 is also at, or below, the top 78 of casterassembly 30. This arrangement effectively gives wheel 39 and casterassembly 30 a low profile with respect to load bearing member 20. Thisarrangement allows rolling support assembly 10 to support an article orload while positioned beneath low-lying structures such as beds, crates,stands, tables, and other similar structures where the clearance abovesupporting surface 60 is minimal.

In the configuration shown, height 80 of caster assembly 30 allowsrolling support assembly 10 to be positioned beneath a low clearanceobject. As shown in FIG. 3, changes to height 72 of wheel 39 effect theoverall height 80 of caster assembly 30. As wheel height 72 increases,the overall height 80 of caster assembly 30 increases. In one preferredembodiment, height 72 of wheel 39 is 2.25 inches making the overallheight 80 of caster assembly 30 about 2.25 inches. Height 80 may includeother structures such as a low profile cover or supporting member thatmay be positioned above caster assembly 30 without making a substantialdifference to height 80. For example, a cover of approximately 0.25inches in thickness over the top of frame 31 may be used withoutsubstantially changing the overall height. Various other embodiments arealso envisioned depending on the materials and design used to constructload bearing member 20 and caster assembly 30. A wheel 39 having aheight as small as 1 inch is also envisioned. Wheels larger than 2.25inches may be desirable depending on the situation. For example, someembodiments may prefer wheels of 3 inches, 5 inches, or greater than 5inches without limitation, and may include solid molded wheels made ofvarious plastics or other polymeric materials, natural or syntheticrubber, wheels formed from carbon fiber, solidified resins, metals,metallic compounds or metal alloys. Also envisioned our wheels 39including tubeless rubber tires, pneumatic tires, or tires filled withvarious liquids or gases and the like.

As shown in the illustrated embodiments in FIGS. 1-3 and describedabove, bearing assembly 51 is maintained within caster assembly 30 byretaining member 52 which extends the entire distance around frame 31.However, other embodiments are envisioned as well for supportingstructures within caster assembly 30 which are also able to maintainbearing assembly 51, and by extension, hub 46 in position. For example,in another embodiment, hub 46 is supported by a circular or semicircularframe at three points around central opening 37, for example with two ofthe three points of support 180 degrees apart with the third positionedalong the frame preferably about halfway between them. The three pointsof support may be embodied as three individual ball bearing assemblies,a single ball bearing assembly having three contact points, threeindividual balls positioned between hub 46 and a frame, or any ofvarious other suitable types of rotatable or pivotal mounting devicesknown to one of ordinary skill in the art. Ball bearing assembly 51, inanother embodiment, is simply a ring of ball bearings wedged between hub46 and frame 31 with notches, flanges, retaining rings, or the likemaintaining the ball bearings in position with respect to both hub 46and a frame.

Similarly, hub 46 is shown extending across central opening 37substantially covering or enclosing central opening 37 except for wheelmount 44 which includes wheel opening 47 within which wheel 39 ispositioned. Other embodiments of hub 46 are also envisioned providingthe same force transferring behavior. For example, in anotherembodiment, hub 46 is ring shaped and pivotally mounted to frame 31 (forexample, by interacting with bearing assembly 51) and includes a wheelmount 44 composed of a single mounting hole for axle 41. In thisembodiment, hub 46 effectively transfers load forces from load bearingmember 20 through frame 31 and wheel 39 to supporting surface 60 eventhough hub 46 does not completely cover central opening 37.

Likewise, caster assembly 30 may support load bearing member 20 by anyof various other configurations. For example, in certain embodiments,load bearing member 20 extends over or above caster assembly 30 whilemaintaining a height 85 that is minimally higher than caster assemblyheight 80 and wheel height 72, for example with a flat cover piece thatrests on frame 31. In these embodiments, load bearing member 20 mayextend over caster assembly 30 partially or completely covering it fromabove. Such an arrangement may be preferable in some instances, forexample, for added strength or protection.

Other embodiments of load bearing member 20 may extend longitudinallybeyond caster assembly 30 forward or sideways. It may also beadvantageous in some situations to increase the width of load bearingmember 20 so as to partially or completely surround caster assembly 30with load bearing member 20. In such cases it may be preferable forincreased stability to widen load bearing member 20 and to laterallydisplace caster assembly 30 along load bearing member 20 rather thanterminating load bearing member 20 at caster assembly 30 as shown inFIGS. 1-3.

Various types of connections between load bearing member 20 and casterassembly 30 are envisioned as well. For example, caster assembly 30 maybe a separate unit configured to be coupled to load bearing member 20 byscrews, bolts, or other non-destructively removable fasteners. Likewise,caster assembly 30 may be attached by means of intermediate devices suchas brackets, fittings, mountings, or other mechanical structures usefulfor aiding in the coupling of load bearing member 20 to caster assembly30. One example of this type of configuration is a load bearing member20 that does not attach directly to frame 31 but rather is attached toan intermediate bracket or cover which is then attached to the topsurface of caster assembly 30 by coupling it to the top surface of frame31. On the other hand, caster assembly 30 may be attached to loadbearing member 20 by more permanent means such as welding, brazing,soldering, or other similar means. Similarly, load bearing member 20 maybe formed such that frame 31 is an integral part of load bearing member20 thus making caster assembly 30 an integral structure within loadbearing member 20.

In FIGS. 4 and 5 are illustrated two different embodiments of examplepatient lifts mounted on rolling support assemblies as embodied in FIGS.1-3. Patient lift 100 may be used to assist a patient to a standingposition. In FIG. 4, patient lift 100 (also schematically illustrated asload 100 in FIG. 2) is mounted to load bearing member 20 and mount 24via a base 101. Patient lift 100 is supported by caster assembly 30 andrear support assembly 500 as shown and described in FIGS. 1-3. Supportaxis SA, load bearing axis LB and rear supporting axis RSA are alsoshown in accordance with the illustrations in FIGS. 1-3. A secondrolling support assembly and load bearing member 20′ is also shown andit should be assumed that all reference identifiers, axes, etc. areduplicated for both rolling support assemblies. In alternativeembodiments with patient lifts or other loads, two or more load bearingassemblies to support devices or structures as disclosed herein may beused.

Patient lift 100 further includes a mast 103 extending vertically awayfrom load bearing member 20 and base 101. A guidance or steering handle105 useful for maneuvering patient lift 100 is also provided and ismounted to mast 103. A lifting device 109 is also coupled to mast 103and is extendable to raise and lower support arm 106. Support arm 106 iscoupled to mast 103 at a support arm pivot joint 104 and is alsoconnected to lifting device 109 at a lifting device pivot joint 111. Apatient load 115 extends from support arm 106, patient load 115 defininga lift axis LI laterally offset from load axis LA towards/over theforward support assemblies. In operation, lifting device 109 changeslength causing support arm 106 to pivot on support arm pivot joint 104thus raising support arm 106 with respect to supporting surface 60. Aswith support axis SA, load axis LA, and rear supporting axis RSAdescribed in detail above, lift axis LI defines the horizontal positionalong the load bearing axis LB of the vertical component of the forcecreated by patient load 115 that is perpendicular to supporting surface60. Lift axis LI may be horizontally offset between load axis LA andsupport axis SA, or it may be offset closer or further from load axis LAthan support axis SA (as viewed in two dimensions as shown in FIG. 2).

A second embodiment of an example patient lift 200 is illustrated inFIG. 5. Patient lift 200 has substantially the same components as appearin patient lift 100 except they are denoted with corresponding 200numbers. As a difference, patient lift 200 may be used to fully supporta patient or load. As with patient lift 100, mast 203 extends verticallyaway from load bearing member 20 and mount 201. A guidance or steeringhandle 205 useful for guiding patient lift 200 is also provided and ismounted to mast 203. A similar lifting device 209 is coupled to mast 203and also operates to raise and lower support arm 206. Support arm 206 iscoupled to mast 203 at a support arm pivot joint 204 and is alsoconnected to lifting device 209 at a lifting device pivot joint 211. Apatient load 215 extends from support arm 206, patient load 215similarly defining a lift axis LI laterally offset from load axis LA. Aswith patient load 100, lifting device 209 raises support arm 206 withrespect to supporting surface 60. As with patient lift 100, lift axis LImay be horizontally offset between load axis LA and support axis SA, orit may be offset closer or further from load axis LA fan support axis SA(as viewed in two dimensions as shown in FIG. 2).

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiment has been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected. In addition, all references cited hereinare indicative of the level of skill in the art and are herebyincorporated by reference in their entirety.

What is claimed is:
 1. A rolling support assembly for an articlecomprising: a longitudinal load bearing member oriented substantiallyparallel to a support surface and defining a height and a load bearingaxis, the load bearing member supporting an article above the supportsurface, and; a caster assembly supporting the load bearing member andhaving a height, the caster assembly having a frame, a hub pivotallymounted to the frame and rotatable around a vertical axis, and a wheelpivotally mounted to the hub and configured to support the casterassembly above the support surface; wherein the load bearing memberextends laterally from the caster assembly.
 2. The rolling supportassembly of claim 1, the wheel further comprising a height defined by anupper extent, wherein the load bearing axis is below the upper extent ofthe wheel.
 3. The rolling support assembly of claim 1 wherein the heightof the load bearing member as it laterally approaches the casterassembly is less than or approximately equal to the height of the casterassembly.
 4. The rolling support assembly of claim 1 wherein the heightof the caster assembly is approximately 2.25 inches or less.
 5. Therolling support assembly of claim 1 wherein the load bearing memberabuts a side wall of the frame.
 6. The rolling support assembly of claim1 wherein the load bearing member extends laterally away from an outersurface of the frame.
 7. A rolling support assembly for supporting aload above a supporting surface comprising: a load bearing membersupporting a load above a support surface, the load bearing memberdefining a load bearing axis and the load defining a load axis thatintersects and is perpendicular to the load bearing axis; a casterassembly having a top and a bottom and supporting the load bearingmember, the caster assembly further including, a frame, a hub, and awheel, the hub being pivotally mounted to the frame and rotatable arounda support axis parallel to the load axis, and the wheel having an upperextent, the wheel being contained within the caster assembly, pivotallymounted to the hub, and configured to support the caster assembly abovethe support surface; wherein the load bearing member extends laterallyaway from the caster assembly; and wherein the support axis is laterallyoffset from the load axis by the horizontal span of the load bearingmember.
 8. The rolling support assembly of claim 7 wherein the loadbearing axis crosses the caster assembly.
 9. The rolling supportassembly of claim 7 wherein the load bearing axis crosses the supportaxis below the upper extent of the caster assembly.
 10. The rollingsupport assembly of claim 7 wherein the load axis is offset from thesupport axis by a distance greater than about half the length of theload bearing member.
 11. The rolling support assembly of claim 7 whereinthe load bearing axis is oriented substantially parallel to thesupporting surface.
 12. The rolling support assembly of claim 7 whereinthe load bearing member abuts a side wall of the caster assembly. 13.The rolling support assembly of claim 7 wherein the load bearing memberextends laterally away from an outer surface of the caster assembly. 14.The rolling support assembly of claim 7 wherein the load is a patientlift having a lift arm supported above the load bearing member by a mastextending vertically away from the load bearing member, and; wherein thelift arm extends laterally away from the mast and supports a patientload, the patient load defining a lift axis laterally offset toward thesupport axis.
 15. A rolling support assembly for supporting an articlecomprising: a load bearing member supporting an article above a supportsurface, and; a caster assembly supporting the load bearing member, thecaster assembly having a height defined by a top and a bottom andfurther including: a frame defining a central opening within the casterassembly, and an outer surface of the caster assembly; a ball bearingassembly coupled to the frame; a hub positioned within the centralopening of the caster assembly, coupled to the ball bearing assembly,and rotatable about a vertical axis of rotation; a wheel pivotallymounted to the hub and rotatable about a horizontal axis of rotation,the wheel also defining a height; wherein the load bearing memberextends laterally away from the outer surface of the frame, and; whereinthe height of the load bearing member and the height of the casterassembly are substantially the same where the load bearing memberapproaches the frame.
 16. The rolling support assembly of claim 15wherein the height of the frame is less than or approximately equal tothe height of the wheel.
 17. The rolling support assembly of claim 15wherein the height of the load bearing member is less than the height ofthe wheel at the point the load bearing member extends away from theframe.
 18. The rolling support assembly of claim 15 wherein the heightof the load bearing member is less than or approximately equal to theheight of the caster assembly at the point the load bearing memberextends away from the caster assembly.
 19. The rolling support assemblyof claim 15 wherein the ball bearing assembly is a four point angularcontact ball bearing assembly.
 20. The rolling support assembly of claim15 wherein the load bearing member abuts a side wall of the casterassembly.